One problem associated with solid propellant rocket motors is that with age their performances may change. Some changes may be only slightly detectable while other changes which were not detected by routine inspection procedures may result in complete failure of the solid propellant rocket motor.
A performance factor often effected is the ignition transits. Usually the change in ignition is a slower pressure rate rise within the solid propellant rocket motor. A controlling factor to this reduced pressure rate rise often relates to changes in the propellant surfaces of the solid propellant rocket motor. Some of the changes often relate to migration of the propellant ingredients to the propellant surfaces. Other changes relate to chemical changes on the propellant surfaces. Either of these changes or a combination of these changes are the primary causes of performance changes.
In order to overcome the deficiencies resulting from migratory changes and/or chemical changes to the solid propellant surfaces, the normal procedure is to redesign the igniter output so that the igniter action "sweeps away" the undesired propellant surface while maintaining the proper pressure within the solid propellant rocket motor. With pyrogen igniters such a redesign results in a change of both hardware and propellant configuration.
Advantageous would be a solution which does not effect pyrogen igniter design which likewise does not result in changes to both the hardware and propellant configuration.
Therefore, an object of this invention is to provide an add-on to an already existing pyrogen igniter that results in a desired ignition of a propellant surface that has undergone changes.
Another object of this invention is to provide an add-on pyrotechnic package that employs a pyrotechnic selected from proven pyrotechnics having compatibility with the solid propellant composition and the solid propellant rocket motor environment with which it is to be used.
A further object of this invention is to provide an add-on pyrotechnic package that is adapted for attaching to the nozzle of a pyrogen igniter so that igniting of the pyrotechnic is effected by the exhaust gases from the pyrogen igniter to thereby provide rapid ignition of the solid propellant and maintain rapid pressure rise of the solid propellant rocket motor in which the pyrogen igniter with the add-on pyrotechnic package is installed.